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1.
Moringa ovalifolia tree is indigenous to Namibia and is a multipurpose tree whose leaves, pods, fruits, and flowers are edible. The tree is well adapted to the harsh climatic conditions of the region and easily cultivated. In this paper, we investigate the physicochemical characteristics of the oil extracted from M. ovalifolia seeds collected from Remhoogte Farm, Khomas region, Namibia. The oil yield was 34.86 ± 2.47%. The oil contained a high level of monounsaturated fatty acids, with oleic acid (18:1) being the dominant one. The oil had high levels of tocopherol, with a total of 44.56 mg 100 g?1 of oil, comprising α‐tocopherol (33.94 mg 100 g?1), β‐tocopherol (6.64 mg 100 g?1), and δ‐tocopherol (3.98 mg 100 g?1). High levels of stigmasterol (142.41 mg 100 g?1) and β‐sitosterol (330.70 mg 100 g?1) were also detected. The seed oil exhibited good‐quality characteristics, making it a useful new seed oil to be considered for food and nonfood applications.  相似文献   

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通过在萤石浮选中增效剂对油酸的增效作用的研究,证明增效剂以低复配比组成的增效油酸,具有低温浮选和抗钙、镁离子干扰的良好的性能。增效油酸的使用,实现了碳酸盐一萤石矿在5℃低温和硅酸盐一萤石矿在3℃低温下的正常浮选。与皂化油酸和超声波乳化油酸相比,具有浮选指标提高和捕收剂量大幅降低的显著效果。  相似文献   

4.
The present prospective study examines proportions of maternal erythrocyte fatty acids across gestation and their association with cord erythrocyte fatty acids in normotensive control (NC) and preeclamptic pregnancies. We hypothesize that maternal fatty acid status in early pregnancy influences fetal fatty acid stores in preeclampsia. 137 NC women and 58 women with preeclampsia were included in this study. Maternal blood was collected at 3 time points during pregnancy (16–20th weeks, 26–30th weeks and at delivery). Cord blood was collected at delivery. Fatty acids were analyzed using gas chromatography. The proportions of maternal erythrocyte α‐linolenic acid, docosahexaenoic acid, nervonic acid, and monounsaturated fatty acids (MUFA) (p < 0.05 for all) were lower while total n‐6 fatty acids were higher (p < 0.05) at 16–20th weeks of gestation in preeclampsia as compared with NC. Cord 18:3n‐3, 22:6n‐3, 24:1n‐9, MUFA, and total n‐3 fatty acids (p < 0.05 for all) were also lower in preeclampsia as compared with NC. A positive association was observed between maternal erythrocyte 22:6n‐3 and 24:1n‐9 at 16–20th weeks with the same fatty acids in cord erythrocytes (p < 0.05 for both) in preeclampsia. Our study for the first time indicates alteration in maternal erythrocyte fatty acids at 16th weeks of gestation which is further reflected in cord erythrocytes at delivery in preeclampsia.  相似文献   

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The lipid content and fatty acid (FA) composition of seeds from the Asian ginseng Panax ginseng growing naturally in taiga forests of the Russian Far East and seeds from cultivated ginseng were studied in this work. The total lipid content of seeds from both wild and cultivated plants was 9–12 % of fresh weight. FA were analyzed as isopropyl esters on a polar capillary column BD‐225, which allows good separation of petroselinic and oleic acids. The structure of FAs was confirmed using GC–MS of fatty acid methyl ester (FAME) and 4,4‐dimethyloxazoline derivatives. In all the seed samples, the major FA was petroselinic acid 18:1(n‐12) which comprised more than 60 %; the contents of oleic and linoleic acids were lower (15–17 and 15–16 %, respectively). Earlier, a higher level (>80 %) of oleic acid had been reported for ginseng seeds. This discrepancy can be explained by an insufficient separation of these acids on standard columns used for GC of FAME. In general, seeds of wild and cultivated ginseng are very similar in lipid content and FA composition.  相似文献   

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Esterification reaction of fatty acids with polyoxyethylenes has been studied in the presence of solid acid catalysts and the results are compared with those obtained with a classical homogeneous catalyst, p-toluene sulphonic acid. Solid acid catalysts showed very high selectivities for monoesters even under less favorable reaction conditions of 1:1 molar ratios of oleic acid to PEG. Excess amount of PEG is normally required to ensure high selectivity for monoesters in the presence of homogeneous catalysts. The yields for monoesters given by heterogeneous catalysts such as zeolites, HPA and nafion were comparable to that with p-toluene sulphonic acid after 24 h of reaction. Results suggest that solid acid catalysts are potential catalysts for selective synthesis of monoesters from oleic acids and PEG even under severe reaction conditions. A screening study of different solid acid catalysts showed ZSM-5, zeolite-β, and nafion to be better catalysts than zeolite USY and mordenite, the former giving higher selectivity and yield to monoesters. The results suggest that the most important parameters in optimization catalyst performance for monoesters production is the acid strength and less so on other properties such as shape selectivity and concentration of active sites.  相似文献   

7.
Free lipase-mediated alcoholysis for biodiesel production has drawn increasing attention in recent years due to its advantages of lower cost and faster reaction rate compared to immobilized lipase. Ethanol, derived from renewable biomass, has a great potential for biodiesel production. A previous study showed that free lipase NS81006 could effectively catalyze the ethanolysis of triglycerides for biodiesel preparation. Since most crude plant oils always contain an amount of free fatty acids, oleic acid was used as the model substrate for this study on lipase-mediated esterification for biodiesel production. The central composite design of the response surface methodology was adopted for process optimization. A biodiesel yield of over 90 % was achieved under optimal reaction conditions and the repeated use of the free lipase was easily realized through phase separation either by natural gravity force or centrifugation.  相似文献   

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Utilization of biomass-derived materials or chemicals plays a significant role in reducing the dependence of unsustainable resources of petroleum and coal. A series of sulfonated glucose-derived solid acids (SGSAs) were developed in this study through a one-step method. These catalysts were characterized by XRD, FT-IR, SEM, and BET to determine their physiochemical properties, and their acid content was measured by acid-base titration. The catalytic performances of SGSA catalysts were evaluated in two esterification reactions:propionic acid or oleic acid with methanol (a typical reaction to upgrade biodiesel). Conversion of oleic acid and selectivity of methyl oleate can reach as high as 93.3% and 94.7% respectively over SGSA-6, which has the highest—SO3H density. Moreover, regeneration of spent catalysts by sulfuric acid solution can significantly enhance their stability and reusability.  相似文献   

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Utilization of biomass-derived materials or chemicals plays a significant role in reducing the dependence of unsustainable resources of petroleum and coal. A series of sulfonated glucose-derived solid acids(SGSAs) were developed in this study through a one-step method. These catalysts were characterized by XRD, FT-IR, SEM,and BET to determine their physiochemical properties, and their acid content was measured by acid–base titration. The catalytic performances of SGSA catalysts were evaluated in two esterification reactions: propionic acid or oleic acid with methanol(a typical reaction to upgrade biodiesel). Conversion of oleic acid and selectivity of methyl oleate can reach as high as 93.3% and 94.7% respectively over SGSA-6, which has the highest -SO_3 H density. Moreover, regeneration of spent catalysts by sulfuric acid solution can significantly enhance their stability and reusability.  相似文献   

10.
Afghanistan is the fourth largest producer of almonds in the world producing 78 native and 6 imported cultivars. However, till date, there have been no comprehensive data on nutrient profiles of the native cultivars. Thus, in the present investigation, tocopherol contents and fatty acid composition from the kernels of 20 selected native almond cultivars of Afghanistan were analyzed. The ranges of variability for the studied nutrients were similar to those already reported for almonds grown in other countries, such as 47.8–66.1% of total lipids (fresh weight basis), 62.54–81.57% of oleic acid in the total lipids, and 139.1–355.0 μg/g α-tocopherol in kernels. With respect to cultivars, significantly (p < 0.05) high content of total lipids were recorded in ‘Belabai’ and ‘Sattarbai’ (Afghan grade), oleic acid in ‘Khairodini’ and of α-tocopherol in ‘Khairodini-161 Samangan’ and ‘Belabai’ cultivars. Kernels from these cultivars can be used for nutrient dense food formulations. Daily consumption of 50 g almonds is sufficient to meet the RDA of α-tocopherol (15 mg/day), considering the average 300 μg/g of α-tocopherol in Afghan almonds. Also, these nutrient rich cultivars can be used in almond breeding programs globally, to focus on improving kernel oil composition and nutrient contents.  相似文献   

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The present study was designed to determine if feeding steers extruded flaxseed and hay (25 and 75%; DM basis) together as a total mixed ration (TMR), or sequentially (non-TMR) would result in different enrichments of polyunsaturated fatty acids (PUFA) and their biohydrogenation intermediates (BHI) in beef adipose tissues [subcutaneous (SC) vs perirenal (PR) fat]. Forty-eight Angus cross steers (325 ± 16 kg) were stratified by weight to six pens, and pens were randomized to either TMR or non-TMR and fed ad libitum for an average of 242 days. The concentrations of α-linolenic acid increased by 18 mol% in both SC and PR in non-TMR steers compared to TMR steers (P < 0.01). trans 18:1 isomers were more concentrated in PR than SC (14.4 vs 9.5 mol%; P < 0.01) and increased by 10 mol% in both fat depots for non-TMR (P < 0.01). Other BHI including non-methylene-interrupted 18:2 (atypical dienes), conjugated linoleic acids and conjugated linolenic acids (CLnA) were affected by diet × tissue interactions (P < 0.01). The CLnA and CLA contents were higher in both fat depots when feeding the non-TMR, but the effect of diet was more pronounced in PR than in SC (P < 0.01). Atypical dienes were highest in PR from non-TMR and lowest in TMR fed steers (4.3 and 3.6 mol%) with SC contents being intermediate. The sequential feeding of lipid supplement can thus profoundly affect the enrichment of PUFA and their BHI in beef fat and their differentially enrichment is also fat depot dependant.  相似文献   

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Previous studies show that long term variations in dietary fat consumption impact circulating fatty acid ethanolamide (FAE) concentrations, however, few studies have investigated short term effects of dietary fat feeding on FAE levels. The trial’s objective was to explore the effect of acute feeding of varying amounts of dietary n-9 and n-3 fatty acids on plasma and organ levels of FAE. Sixty-four rats were assigned to four groups fed meals containing 40% of energy as either safflower oil (control), canola oil (CO), or DHA rich oil (DRO), each consumed as a bolus within a 2-h window. Plasma and tissue FAE levels were measured at 3, 6, 12 and 24 h following the bolus. FAE profiles over time exhibited patterns that were specific both to FAE and to dietary fat type provided. At 3 h, plasma and liver OEA levels were higher (p < 0.05) in the 95% CO:5% DRO compared with other groups. At 12 h, plasma PEA levels were lower (p < 0.05) in the 50% CO:50% DRO group compared to the 95% CO group. Plasma DEA levels showed an increase (p < 0.05) only after 24 h of feeding. All four dietary groups manifested increased DEA levels in a dose-dependent manner. Data demonstrate that a single meal feeding of diets with different ratios of fat types impacts tissue levels of FAE within a short time frame, which could further influence the physiological roles of FAE on appetite regulation and energy expenditure.  相似文献   

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We analyzed the unsaturated fatty acids oleic (OA, 18:1n‐9) and linoleic (LA, 18:2n‐3), and a 3:1 LA:OA mixture from ?100 to 50 °C with continuous gradient temperature Raman spectroscopy (GTRS). The 20 Mb three‐dimensional data arrays with 0.2 °C increments and first/second derivatives allowed rapid, complete assignment of solid, liquid, and transition state vibrational modes. For OA, large spectral and line width changes occurred in the solid state γ to α transition near ?4 °C, and the melt (13 °C) over a range of only 1 °C. For LA, major intensity reductions from 200 to 1750 cm?1 and some peak shifts marked one solid state phase transition at ?50 °C. A second solid state transition (?33 °C) had minor spectral changes. Large spectral and line width changes occurred at the melt transition (?7 °C) over a narrow temperature range. For both molecules, melting initiates at the diene structure, then progresses towards the ends. In the 3:1 LA:OA mixture, some less intense and lower frequencies present in the individual lipids are weaker or absent. For example, modes assignable to C8 rocking, C9H–C10H wagging, C10H–C11H wagging, and CH3 rocking are present in OA but absent in LA:OA. Our data quantify the concept of lipid premelting and identify the flexible structures within OA and LA, which have characteristic vibrational modes beginning at cryogenic temperatures.  相似文献   

16.
不同碳氮组合对小球藻异养培养油脂积累的影响   总被引:1,自引:0,他引:1  
目的探讨不同碳氮组合对小球藻Chlorella pro tothecoides CS-41异养培养油脂积累的影响。方法以不同浓度葡萄糖为碳源,尿素为氮源,异养培养小球藻,采用干重法测定小球藻生物量,氯仿/甲醇法提取总脂,并采用GC-MS分析脂肪酸含量。结果小球藻最佳生长条件的碳氮组合配比为葡萄糖浓度40g/L,尿素浓度3g/L,此时小球藻生物量达最高,为9.1g/L,脂肪酸产率最大,为1.26g/L;总脂含量最高,为4.38g/L。结论获得了碳氮最佳配比,使小球藻脂肪酸含量提高到1.26g/L,为发酵扩大化培养小球藻制备生物柴油奠定了基础。  相似文献   

17.
Vegetable oils can be deacidified by liquid–liquid extraction based on differences in polarity between triglycerides and fatty acids and differences in solubility. Information on the equilibrium between the phases of such systems is important for designing separation processes. The present paper reports experimental data for the extraction of fatty acid from soybean oil by (ethanol + water) as a mixed-solvent for system of soybean oil + oleic acid + ethanol + water at 30 °C at different water contents. The liquid–liquid equilibrium data of the systems were used to obtain interaction parameters in the universal quasi-chemical theory (UNIQUAC) activity coefficient model. These parameters can be used to predict equilibrium data of ternary and quaternary systems. The deviations between experimental and calculated compositions in both phases for each system using this model were calculated. The distribution coefficients and the selectivity factors of solvents for extraction of fatty acid from oil at 30 °C were calculated. Increasing of the water content as the co-solvent decreased the distribution coefficients and increased the selectivity factors of mixed-solvents, therefore considering the economical and practical aspects the optimum water content may be used for extracting oleic acid from soybean oil. We concluded that (ethanol + water) as a mixed-solvent can be used for extracting fatty acids from edible oils in a normal temperature.  相似文献   

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孙峰  尹少华 《当代化工》2012,41(5):455-456,459
以油酸为原料,高锰酸绅为氧化剂,经氧化分解、沸水萃取、活性炭吸附脱色等过程制备壬二酸的最佳反应条件为:n(油酸)/n(高锰酸钾)=0.2:1~0.25:1,温度为50℃,m(油酸)/m(苄基三乙基氯化氨)=10:1,氧化10h,壬二酸收率大约为35%;在此条件下,增加超声波辅助手段,收率增加了10%~ 16%左右,壬二酸收率可达到50%.  相似文献   

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Epoxidized methyl esters (EMO) with their high oxirane ring reactivity, acts as a raw material in the synthesis of various industrial chemicals including polymers, stabilizers, plasticizers, glycols, polyols, carbonyl compounds, biolubricants etc. EMO has been generally quantified by the gas chromatography (GC) and high-performance liquid chromatography (HPLC) techniques. Taking into the account of the limitations of these techniques, two qHNMR-based equations have been proposed for the quantification of EMO in the mixture of EMO and methylesters (MO). The validity of the proposed method was determined using standard mixtures of MO and EMO having different molar concentrations. The developed equations have been applied on the samples of EMO prepared from oleic acid in two-step process viz., esterification followed by epoxidation. The qHNMR-based EMO quantification showed acceptable agreement with the results obtained from HPLC analysis.  相似文献   

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